Cardiac disease continues to be a very serious medical problem affecting large numbers of people. One common type of cardiac problem is atrial fibrillation. Normally, the heart contracts and relaxes to a regular beat. In atrial fibrillation, the heart beats rapidly, with an irregular beat. Atrial fibrillation can have many causes. For example, hypertension, fatigue and infection can lead to atrial fibrillation. As with many other diseases, early detection of cardiac disease is extremely important.
Some types of cardiac disease have known precursors that can be used to determine a future likelihood of illness. For example, one precursor of atrial fibrillation is fibrosis in the atrial wall of the heart. Fibrosis is, in general, the formation of fibrous, scar like tissue. When a scar tissue is formed in the atrial wall, it can lead to variety of cardiac problems, including atrial fibrillation.
Another precursor of atrial fibrillation is electrical instability in the atrial wall. Electrical instability in the atrial wall can lead to a shortened refractory periods, which in turn are a precursor to atrial fibrillation.
Because fibrosis and electrical instability in the atrial wall can lead to cardiac disease, characterization of the atrial wall that can detect these conditions is highly desirable. Thus, there is a continuing need for improved systems and method for characterizing the health of atrial walls in the heart.